<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>模板</title>
  </head>
  <body>
    <!-- 准备好一个容器 -->
    <div id="test"></div>

    <!-- 引入react核心库 -->
    <script type="text/javascript" src="../js/react.development.js"></script>
    <!-- 引入react-dom，用于支持react操作DOM -->
    <script
      type="text/javascript"
      src="../js/react-dom.development.js"
    ></script>
    <!-- 引入babel，用于将jsx转换成js -->
    <script type="text/javascript" src="../js/babel.min.js"></script>
    <script type="text/babel">
      class Demo extends React.Component {
        /**
         * React.createRef调用后返回一个容器，该容器可以存储被ref所标识的节点
         * 容器内只能存一个节点
         */
        myRef = React.createRef();

        showInput = () => {
          console.log(this.myRef.current.value);
        };

        render() {
          return (
            <div>
              <input ref={this.myRef} type="text" placeholder="录入数据" />
              <button onClick={this.showInput}>点击展示</button>
            </div>
          );
        }
      }

      ReactDOM.render(<Demo />, document.querySelector("#test"));
    </script>
  </body>
</html>
